I suppose it is only appropriate that I begin by introducing myself. So who am I?
I was considering this apparently profound question last night. It seems to me that it requires a complex answer - and far more thought than we give it on a day-to-day basis. What does it mean to be 'you'?
As a hatchling biologist, my first reaction is to ask the question 'nature or nurture?' Well I've thought about this before - it's either one or the other - but it all depends on how you define each part of the question. What constitutes 'nurture'? If 'nurture' means strictly how your parents raise you - not the environment in general - and 'nature' is all that is 'natural' - your biology - then the answer must be 'nature'. After all, humans are the product of their evolution. If you go back far enough, there are no 'nurturing parents' at all. Bacteria do not exactly care for their young - mitosis makes that impossible.
On the other hand, define 'nurture' as 'the environment', and I must draw the opposite conclusion. After all, go back even further, and what were we? Organic molecules - and further back? We weren't exactly alive - a product purely of the 'environment'. 'Nature' derived from 'nurture'.
Of course, it is absurd to think in these terms. When I'm not reducing things ridiculously, I apprecaite that it is both 'nature' and 'nurture' that add to what and 'who' we are. I am certain that a huge part of who I am is in my genes - or at least resulted from the effects of the environment on my genes at a very early stage in my development. Now, however, I am more evidently affected by my day-to-day experiences. My brain, in particular, develops with each new piece of information I receive. Again, though, my genes set the limits - there's a reason you can't teach a dog to speak English.
So, ok, part of me is to do with my genetic make-up and part is to do with the effects of my environment on that basic blank slate. But there's even more to it.
If I am ultimately a machine - a bunch of molecules working together according to natural laws, I am also just a bunch of atoms that obey the laws of physics. But think about that for a moment. Atoms are not stationary things. Neither are their components. From one moment to the next, the components that make 'me' up reshuffle, are lost, replaced. Even complete molecules and cells are lost and replaced through-out any person's lifetime.
If you compare your constituents now to those you were made of when you were born, they would not be the same. Well now, that's amazing! Being 'you' isn't even static. From moment to moment, 'you' are changing.
Now let me digress a little... Though it sounds impressively like science fiction, it has been suggested that, perhaps, in the future it will be possible to make 'back-ups' of our personalities and upload them onto computers. When we die, therefore, we will effectively live on. This idea, while beautiful, disturbs me. If I were one of these future peoples, I would love to have a personality back-up - but would that be me? I feel that it would just be a 'copy'. I would still be standing there after its upload right? It has to be a copy.
And thus, back to my point - moment to moment, you have a 'copy' of yourself being 'created', in effect. We may each feel that we do not change, but we are in fact constantly in flux. Not only are 'you' no longer in existence from moment to moment, your new 'copy' is also slightly different to 'you'.
The conclusion? Well I'm not too sure. I think there's more to explore. Even if you are appalled by my death-defying (quite literally, in this case) leaps and assumptions, perhaps you've found something to think about.
Jtcgh
Ah, the always fascinating concept of a transhuman stage thanks to technological evolution of the human mind...
As I have a somewhat strong fear of death, it's something I've strongly considered in the past, although more along the lines of a gradual replacement of my existing nervous system with artificial neurones, and an eventual download of my 'primary' consious, rather than a copy.
Still, there is still the same fear in my mind that you mention: How will I know that at the end of the process, what will result is not merely something that merely *thinks* like me, rather than being me?
Frankly, when faced with death I would always think the risk is justifiable, but I would always wonder, even afterwards whether I am still me.
Although I see your argument with us as humans being in flux, I can't personally accept it. I have often wondered if I am a constant thing, rather than a newly-spawned and short-lived consious which remembers all that has been done by the previous incarnations of my mind. But nevertheless, I do not believe that to be true, though I accept it as possible.
Simply put, my mind refuses to believe I'm not who I think I am. To deny that I am, and always have been a constant identity would be for my mind to deny the truth to its existence, in a way.
For this same reason, although I find concepts and ideas such as simulation theory interesting, I cannot believe them to be true, because my mind and I will not accept that we're real.
To respond to your comment on humans as machines, I must say that I agree in part, but disagree in terms of the mind.
Whether it's philisophical, or perhaps poetic to be doing so, I believe that there's more to the human mind, and sentience itself than the phisiological 'machinary'.
The simplest way to justify this would be by returning to death: After a mind dies, the actual 'nuts and bolts' - the brain - remains whole and in most cases in good shape, and yet even if you were to supply the dead brain with all the 'fuel' it would normally run on in life, there would be no way to resuscitate the mind; no way to bring back the consiousness.
And that leads me to believe that there's more there than meets the eye.
-Jt